Help to improve my video
I think most of your blurring is coming from the denoising post-process.

firstly, make sure motion blur is not turned on.

To avoid blurriness from the denoising, you have to increase your sampling.

256 or 512 should do it,. but will take a lot longer to render.

Alternatively, try using Blender 2.8 and use the EEVEE renderer. It is so much faster - and your scene doesnt require any complex light paths, so it should work really well.

Good luck!